Yes, these bottles ARE more expensive, but they are so worth it! My baby has used these since three weeks after birth, and she has NEVER had colic or fussiness/gassiness. The vent is the most wonderful feature! The nipples are also very soft. Despite what other reviewers stated, I found that these bottles and vents were very easy to clean and put together. If the bottle is leaking or nipple is collapsing, it's not put together right! Once the vent is together tightly, you should not have leaks. My daughter is now 6 months old and can hold the 9 oz bottle by herself - they're lightweight. The great thing is that BornFree also makes a piece that will attach right to your breastpump, so this makes it so easy to pump right into your BornFree bottles! We love these bottles and would recommend them to everyone! Not only are they the perfect bottle, but they are BPA free, too!! You won't regret spending the extra money on this product.